Skip to main content
Log in

High-throughput transgene copy number estimation by competitive PCR

  • Protocols
  • Published:
Plant Molecular Biology Reporter Aims and scope Submit manuscript

Abstract

Transgene copy number affects the level and stability of gene expression. Therefore, it is important to determine the copy number of each transgenic line. Polymerase chain reaction (PCR) is widely employed to quantify amounts of target sequences. Although PCR is not inherently quantitative, various means of overcoming this limitation have been devised. Recent real-time PCR methods are rapid; however, they typically lack a suitable internal standard, limit the size of the target sequence, and require expensive specialized equipment. Competitive PCR techniques avoid these problems, but traditional competitive methods are time consuming. Here we apply mathematical modeling to create a rapid, simple, and inexpensive copy number determination method that retains the robustness of competitive PCR.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Abbreviations

CCQ-PCR:

continuous competitive quantitative-polymerase chain reaction

References

  • Allen GC, Hall GJ, Michalowski S, Newman W, Spiker S, Weissinger AK, and Thompson WF (1996) High-level transgene expression in plant cells: Effects of a strong scaffold attachment region from tobacco. Plant Cell 8: 899–913.

    PubMed  CAS  Google Scholar 

  • Al-Robaiy S, Rupf S, and Eschrish K (2001) Rapid competitive PCR using melting curve analysis for DNA quantification. BioTech 31: 1382–1388.

    CAS  Google Scholar 

  • Arumuganathan K and Earle ED (1991) Nuclear DNA content of some important plant species. Plant Mol Biol Rep 9: 208–218.

    Article  CAS  Google Scholar 

  • Bonin AL, Gossen M, and Bujard H (1994)Photinus pyralis luciferase: vectors that contain a modifiedluc coding sequence allowing convenient transfer into other systems. Gene 141: 75–77.

    Article  PubMed  CAS  Google Scholar 

  • Burden RL and Faires JD (1993) Numerical Analysis, pp. PWS-Kent, Boston.

    Google Scholar 

  • Callaway AS (1998) A genetic approach to study host factors of Arabidopsis (Arabidopsis thaliana) that influence susceptibility toCauliflower mosaic virus. Ph.D. Dissertation. Cornell University, Ithaca, NY.

    Google Scholar 

  • Davis PJ and Polonsky I (1972) Numerical Interpolation, Differentiation, and Integration. In: Abramowitz M and Stegun IA (eds), Handbook of Mathematical Functions, pp 878, Dover Publications, Inc., New York.

    Google Scholar 

  • Gatz C, Kaiser A, and Wendenberg R (1991) Regulation of a modified CaMV 35S promoter by the Tn10-encoded Tet repressor in transgenic tobacco. Mol Gen Genet 227: 229–237.

    Article  PubMed  CAS  Google Scholar 

  • Gatz C, Frohberg C, and Wendenburg R (1992) Stringent repression and homogeneous de-repression by tetracycline of a modified CaMV 35S promoter in intact transgenic tobacco plants. Plant J 2: 397–404.

    PubMed  CAS  Google Scholar 

  • Gossen M and Bujard H (1992) Tight control of gene expression in mammalian cells by tetracycline-responsive promoters. Proc Natl Acad Sci USA 89: 5547–5551.

    Article  PubMed  CAS  Google Scholar 

  • Ingham DJ, Beer S, Money S, and Hansen G (2001) Quantitative real-time PCR assay for determining transgene copy number in transformed plants. BioTech 31: 132–140.

    CAS  Google Scholar 

  • Jefferson RA, Kavanagh TA, and Bevan MW (1987) GUS fusions: β-glucuronidase as a sensitive and versatile gene fusion marker in higher plants. EMBO J 6: 3901–3907.

    PubMed  CAS  Google Scholar 

  • Kooter JM, Matzke MA, and Meyer P (1999) Listening to the silent genes: transgene silencing, gene regulation and pathogen control. TIPS 4: 340–347.

    Google Scholar 

  • Linz U (1990) Thermocycler temperature variation invalidates PCR results. BioTech 9: 286–293.

    CAS  Google Scholar 

  • Livak K, Flood SJA, Marmaro J, Giusti W, and Deetz K (1995) Oligonucleotides with fluorescent dyes at opposite ends provide a quenched probe system useful for detecting PCR product and nucleic acid hybridization. PCR Methods and Applications 4: 357–362.

    Article  PubMed  CAS  Google Scholar 

  • Ludwig W and Schleifer K-H (2000) How quantitative is quantitative PCR with respect to cell counts? System Appl Microbiol 23: 556–562.

    Article  CAS  Google Scholar 

  • Mandel T, Fleming AJ, Kranhenbuhl R, and Kuhlemeier C (1995) Definition of constitutive gene expression in plants: the translation initiation factor 4A gene as a model. Plant Mol Biol 29: 995–1004.

    Article  PubMed  CAS  Google Scholar 

  • Piatak MJ, Saag MS, Yang LC, Clark SJ, Kappes JC, Luk K-C, Hahn BH, Shaw GM, and Lifson JD (1993) High levels of HIV-1 in plasma during all stages of infection determined by competitive PCR. Science 259: 1749–1754.

    Article  PubMed  CAS  Google Scholar 

  • Raeymaekers L (2000) Basic principles of quantitative PCR. Mol Biotech 15: 115–122.

    Article  CAS  Google Scholar 

  • Sit TL, Haikal PR, Callaway AS, and Lommel SA (2001) A single amino acid mutation in theCarnation Ringspot Virus capsid protein allows virion formation but prevents systemic infection. J Virol 75: 9538–9542.

    Article  PubMed  CAS  Google Scholar 

  • Souazé F, Ntodou-Thomé A, Tran CY, Rostène W, and Forgez P (1996) Quantitative RT-PCR: Limits and accuracy. BioTech 21: 280–285.

    Google Scholar 

  • Wang AM, Doyle MV, and Mark DF (1989) Quantitation of mRNA by the polymerase chain reaction. Proc Natl Acad Sci USA 86: 9717–9721.

    Article  PubMed  CAS  Google Scholar 

  • Zimmermann K and Mannhalter JW (1996) Technical aspects of quantitative competitive PCR. BioTech 21: 268–279.

    CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Anton S. Callaway.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Callaway, A.S., Abranches, R., Scroggs, J. et al. High-throughput transgene copy number estimation by competitive PCR. Plant Mol Biol Rep 20, 265–277 (2002). https://doi.org/10.1007/BF02782462

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02782462

Key words

Navigation